Hi,
Mono 2.0 (Preview 1) is available for download on http://mono.ximian.com/monobuild/preview/download-preview/
This includes a lot of improvements over version 1.9 including my work on supporting mixed-mode assemblies.
Please try it. Feedback is welcome, version 2.0 has not been released yet.
Note that MSVCRT is not yet supported.
There are some test projects in the SVN repository available at http://anonsvn.mono-project.com/viewcvs/trunk/mono/mono/tests/mixed-mode/
Only MixedModeApp and MixedModeLibrary are supposed to work.
Kornél